Let-off mechanism for looms



C. H. DRAPER LET-OFF MECHANISM FOR LOOMS Filed May 5, 1927 3Sheets-Sheet May 22, 1928. 1,670,655

c. H. DRAPER LET-OFF MECHANISM FOR LOOMS Filed May 5, 1927 3Sheets-Sheet 3 Patented May 22, 1928.

UNITED STATES PATENT OFFICE.

TION OF MAINE.

ASSIGNOR, BY MESNE ASSIGN- MASSACHUSETTS, A CORPORA- LET-OFF MECHANISMFOR 1001718.-

Application filed May 3,

The present invention relates to an im provement in let-off mechanismfor looms.

The object of the invention is to produce a new form of let-off which isentirely controlled by the tension of the warp, and which isparticularly adapted for silk or rayon,

although it may also be used on looms for weaving other materials. Theinvention consists in the construction hereinafter described andparticularly defined in the claims.

In the accompanying drawings illustrating the preferred form of theinvention, Fig. 1 is an end elevation of the rear portion of a loomshowing the mechanism; Fig. 2 is a rear elevation of a loom with theparts in position; and Fig. 3 is a view similar to Fig. 1 showing amodified form of the invention.

The illustrated embodiment of the invention is described as follows:This let-otf construction depends for its operation upon the tension ofthe warp. iVhen the warp tension reaches a certain amount it turns thewarp beam to cause it to give up the warp, and thereby causes theimpingement of a part of the mechanism carried by the warp earn againsta stationary part of the loom, which operates an escapement to permitfurther rotation of the beam in a direction to give up the warp. Theloom frame 10 supports the whip roll 11 on the bracket 12. The warp 13passes over this whip roll, which is stationary and held in a fixedposition to the warp beam 14. The warp beam is provided on its ends withescapement wheels 15, which form end disks for the beam. The gudgeons 16of the warp beam are received in the open bearings 17 which are formedin adjustable gudgeon supports 20, bolted at 21 to the bracket arm 22secured t0 the frame of the loom. The slots in the bracket arm 22 andgudgeon su port 20 provide vertical and horizontal aqustment of theposition of the warp beam on the loom.

Mounted on the gudgeons are two escapement arms 23, whose bosses 24 slipover and are pivoted on the gudgeons between the end of the warp beamandthe bearings 17. These escapement arms 23 are provided at their upperends with an escapement pivot 1927. Serial No. 188,493.

pin 25, to which are secured the escapement lever 26 and the release arm27, the pin itself being rotatably mounted in a boss formed at the upperportion of the escapement carrying arms 23. The escapement lever isprovided on its right-hand end, as seen in Fig. 1, with a holding tooth28, and on its left-hand end with a restraining tooth 29. The tension ofthe warp 13 tends to hold the holding tooth 28 in engagement with one ofthe teeth of the ratchet wheel 15, and this tends to rotate the warpbeam in a direction to cause it to exert a pull upon the warp. \Vhen thewarp is drawn throu h the loom by the process of weaving, tie warp beamis turned to the left, as viewed in Fig. 1, until the release arm 27strikes the stop pin 30, adjustably mounted in the bracket 31 secured tothe frame of the loom. Upon the engagement of the release arm with thestop pin the holding tooth of the escapement lever is withdrawn fromengagement with a given tooth of the ratchet wheel 15, and at the sametime the restraining tooth 29 is brought into engagement with theopposite side of another tooth which prevents over-running of the warpbeam due to the tension of the warp. The release of the holding tooth isimmediately followed by its re-engagement with the next successivetoot-h of the ratchet wheel owing to means which are provided tending toturn the escapement arm to the right so that tension is alwaysmaintained upon the warp either by the holding tooth or the restrainingtooth of the escapement lever 26.

The weight is employed to act on the escapement arm in a direction totend to move it to resist the tension of the warp. The mode of applyingthis weight to the escapement arm is as follows: Beyond the pivot pin 25the escapement arm is continued in an inclined direction to the originaldirection of the escapement arm at 32. The end of this extension isprovided with a slotted head 33. To the extension 32 of the es oapementarm 23 is pivotally attached a secondary part 34 of the same arm whichis bolted to the extension by a bolt 35 which extends through thesecondary arm 34 and throu h the slot in the head 33, whereby thesecondary portion 34 of the arm may be adjusted to different positionswith respect to the extension. To the upper end of the extension 34 at36 is pivotally attached the upper end of the weight link 37. The wholeescapement arm comprises the arm proper pull upon the escapement arm.From the lower end of each weight link there extends a short arm l3, tothe end of which is pivotally attached an arm l-L. carrying an openhearing 45 for a second roller 46, the pintles of which are received inthe open hearing. The arm 44 and its bearing carry another arm {17 forsupporting the weight. S-hooks 5O hang on the pins 51 of the arms 47,and the hooks at the lower ends of these S-hoolcs engage the eyes 52formed upon the castings that car the wei ht bar 53. \Veights 54 areslippe over the ar. Upon the lower side of the eye castings 52 may beformed the feet or standards 55, upon which the whole weight bar maystand when desired.

The rollers are made of wood, and are tapered from the center to theends, being of an inch smaller at their ends than in the center, so thatalthough they may spring under the pressure exerted on them by theweight pressing them against the surface of the warp on the beam, theywill still press continuously upon the warp from end to end of the same.

The weight links 37 are angularly formed for the purpose of. equalizingthe. tension exerted on the warp by the weight, irrespective of thediameter of the warp beam at an given time. \Vhen the warp beam islarge, both of the rollers 42 and 4'6 will engage the warp beam, and theleverage on the escapement arm will be less than when the diameter ofthe warp beam is small.

In operation it will be seen that as the warp is gradually consumed, theescapement arms are turned to the left and the weight is lifted untilthe release arms strike the stop pins, whereupon the holding teeth ofthe escapement are withdrawn from engagement with the teeth of theratchet wheels, and are re-engaged with the next teeth. This involves abackward and forward movement of the escapement arm which moves with theholding tooth toward the left until the ratchet wheel tooth is released.whereupon the escapement arm again moves to the right and causes theholding tooth of the escapement lever 26 to engage the next tooth of theratchet wheel, continuously applying resisting pressure to the beam asthe releasing tooth 29 operates to engage the face of a rachet wheeltooth at about the time the holding tooth is released from the face ofanother advancing ratchet wheel tooth. A continuous warp tension iS thusmaintained which is dependent upon the amount of weight applied, anddoes not vary with the diameter of the warp beam at any given time.

When a warp is exhausted and the loom is stopped, the operative takeshold of the ears of the release arms and works them back and forth,thereby gradually releasing the tension on the warp until the extensions32' of the esca ement arms 23 strike the stops 56, carried y the rods 57bolted to the loom frame at 60. The weight is then removed from theweight links, the rollers 42 and 46 are removed from their bearings, oneend of the warp beam is lifted so as to remove the gudgeon from thebearing 17, whereupon the boss 24 is slipped off of the gudgeon on thatend of the beam. A similar operation performed at the other end re'movesthe other weight link and associated part-from the gudgeon on the otherend of the warp beam. Then the warp beam is taken out of" the loom and anew one put in place. One end is raised, and the head 24 of theescapement arm is slipped on to the gudgeon on both ends of the beam,and the beam is turned after the front end of the warp is made fast tothe take-up mechanism, until the tension is again applied to the warp,after which the rollers 42 and 46 are replaced, and the weights areagain put in place.

A feature of this invention resides in the fact that the warp issubjected to tension by means of mechanism which is directly hung uponthe warp beam, and which operates from time to time with exhaustion 0the warp to pay out the warp specifically by the use of an escapementmechanism which permits the turning of the warp beam while maintaing atall times the tension on the warp. More specifically the inventioncontemplates the employment of an escapement mechanism on the warp beamoperating continuously to exert a tension upon the warp, and at the sametime to permit the turning of the warp beam by theo eration of theescapement as the warp is ex austed.

It is to be further observed that there are no friction parts which areemployed to resist the letting-off of the warp, but that such resistanceis secured by the application of a weighted mechanism which swingsfreely under the tension of the warp, only being resisted by a weightwhich resists such tension so that uniformity of warp tension issecured, whereas where friction devices are employed in let-offs, thefriction devices require constant adjustment in order to Secure theproper warp tension. It is believed that this is the first let-offmechanism acting to resist the tension of the warp solely by means of aweight so applied as to cause a uniform tension to be applied to thewarp at all times during the weaving.

In the illustrated embodiment of the invention the escapement employedis one in which a toothed escapement is used, but it is apparent that,viewed in its broader aspects, other devices for holding the escapementarm from motion with respect to the warp beam might be employed.

The invention finds embodiment in the construction illustrated in Figs.1 and 2 as thus far described. It also finds embodiment in theconstruction illustrated in Fig. 3, in which the means for controllingthe escapement is different. The entire mechanism with the exception ofparts referred to, is the same as in the mechanism illustrated in Figs.1 and 2. In this modified form, however the release arm 70, mounted onthe pivot pin 25 is provided with a rearwardly extending portion adaptedto be engaged by the hand of the operator so that the escapement may beconveniently actuated manually. This release arm is also provided with aforwardly extending arm 71 adapted to be engaged by the rearwardlyextended end 72 of the lever 73, the forward end 74: of which isactuated by the cam 75 on the cam shaft 76 of the loom. This lever 73 ispivotally mounted at 77 upon the bracket 78 bolted on the frame of theloom. This lever 73 is an escapement hammer, and is continuouslyoscillated in the operation of the loom to cause its rear end to riseand fall. As the warp is consumed the escapement arms 23 are turned tothe left, and the weight is lifted until the forward end 71 of therelease arm 70 is moved under the rear end 72 of the escapement hammeror lever 73. Thereupon, on the next downward movement of the rear end 72of the escapement hammer the release arm 70. is turned, whereupon theholding teeth of the escapement are withdrawn from engagement with theteeth of the ratchet wheels and are re-engaged with the next teeth. Thisinvolves the same backward and forward movement of the escapement armwhich moves with the holding teeth toward the left until the ratchetwheel tooth is released, whereupon the escapement arm again moves to theright and causes the holding teeth of the escapement lever 26 to engagethe next tooth of the ratchet wheel, continuously applying resistingpressure to the beam as the releasing tooth 29 operates to engage theface of a ratchet wheel tooth at about the time the holding tooth isreleased from the face of another advancing ratchet wheel tooth. Acontinuous warp tension is thus maintained with this con struction aswith the construction of Figs. 1 and ,2, which is dependent upon theamount of weight applied, and does not vary with the diameter of thewarp beam at any given time.

Havin thus described the what is c aimed is:

1. A let-off for looms having, in combination, a warp beam provided withan escapement disk, an escapement arm pivoted concentrically withrelation to the disk, escapement connections between the escapement armand the disk, a weight tending to move the escapement arm in thedirection to resist the pull of the warp, operating automatically uponconsumption of the warp to release the escapement from time to time andre-apply it so as to secure the gradual letting-off of the warp underthe restraint of the weight.

2. Let-off mechanism for looms havin invention,

'p 1 u o 7 in combination, a warp beam provided wit an escapement wheel,an escapement having teeth for alternating engagement with theescapement wheel, a carrier for said escapement, means for operating theescapement when the escapement is moved a predetermined distance so asto permit the movement of the escapement wheel to pay otl' the warp, andweighting means connected with the escapement carrier to restrain themovement of the escapement wheel in a direction to let-off the warp.

A let-off for looms having, in combination, a warp beam provided with anescapement wheel, an escapement lever havin a holding tooth at one endand a restraimng tooth at the other adapted alternately to engage theteeth of the escapement wheel, a carrier for the escapement, a weightconnected with the escapement tending to move it in a direction to causeit to apply tension to the warp, and means for actuating the escapementupon movement of the escapement wheel for a certain arcuate distance.

4. Let-oil mechanism for looms having, in combination, a warp beamprovided'with an escapement wheel, a weight actuated arm adapted toexert a continuous rotative force upon the warp beam in the warp windingdirect-ion to exert tension on the warp, means connected to said weightactuated arm and adapted to engage the teeth of the escapement wheel,and means actuated ,by the tension of the warp to o erate said toothengaging means to pay 0 the warp stepby-step.

5. Let-ofi' mechanism for looms having, in combination, a warp beamprovided with an escapement wheel, a weight actuated arm adapted toexert a continuous rotative force upon the warp beam in the warp windingdirection to exert tension on the warp, means upon said arm adapted toengage the teeth of the escapement wheel, and means actuated by thetension of the warp to shift said arm and thereby actuate the toothengaging means to pay off the warp.

6. Let-ofi' mechanism for looms having, in combination, a warp beamprovided with anescapement wheel, an arm adapted to exert a continuousrotative force upon the warp beam in the warp Winding direction to exerttension on the warp, an escapement associated with said arm and adaptedto engage the teeth of the escapcment wheel,

means actuated by the tension of the warp to operate said escapcment topay off the 0 warp, a weight acting upon said arm to tension the warp,and means adapted to erigage the warp on the beam and shift said weightto vary its action upon said arm.

CLARE DRAPEB.

